Thread-controlling mechanism for sewing-machines.



No. 631,924. H Patented Aug. 29, i899.

J.-E. BERTRAND.

THREAD CONTROLLING MECHANISM FOR SEWING MACHINES.

(Application filed June 2, 18994 (No Model.)

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UNITED STATES PATENT FEIcE.

JOSEPH E. BERTRAND, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE BAY STATE SHOE MACHINERY COMPANY, OF SAME PLACE AND PORT- LAND, MAINE.

THREAD-CONTROLLING MECHANISM FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent NO. $31,924:, dated August 29, 1899.

Original application filed February '7, 1899; Serial No 704,812- Divided and this application filed June 2, 1899- Serial No.

719,078. (No model.)

To (all whom it may concern.-

Be it known that I, JOSEPH ELI BERTRAND, of Boston, in the county of Suffolkand State of Massachusetts, have invented certain new and useful Improvements in Thread-Controlling Mechanism for Sewing-Machines,of which the following, taken in connection with the accompanying drawings, is a specification. i

My invention relates to thread-controlling mechanism for sewing-machines, is a division of my application, Serial No. 70l,8l2, filed February 7, 1899, and is an improvement upon the invention described and illustrated in Patent No. 618,372,.granted to me January 24, 1899; and it consists in certain novel features of construction, arrangement, and combination of parts,which will be readily understood by reference to the description of the accompanying drawings and to the claims hereto appended, and in which my invention is clearly pointed out.

Figure 1 of the drawings is a side elevation of a lock-stitch sewing-machine, illustrating my invention. Fig. 2 is an elevation of the opposite side of so much of the machine as is necessary to illustrate my improved threadcontrolling mechanism, drawn to an enlarged scale. Fig. 3 is a sectional plan of the same parts that are shown in Fig. 2. Fig. 4 is an elevation of the vertically-movable sheave and its carrier to be adj ustably mounted in a bearing in the rear extension of the awl-operating lever. Fig. 5 is an enlarged sectional view of the thread-guiding sheave provided with ratchet-teeth to be engaged by a stoppawl, as will be hereinafter described.

In the drawings, A is the base-plate of the frame of the head of the machine, provided with the upwardly-proj ecting plate-like standard A and firmly secured to a suitable supporting-column B of any suitable construction. The base-plate A has set therein two colu mns in bearings, in the upper end of which is mounted the shaft C, one only, A of said columns being shown'in the drawings. The

shaft 0 has firmly secured thereon the necessary cams for operating the several moving parts of the machine, substantially as shown and described in the before-cited application.

D is the feed-slide, to which a reciprocating motion is imparted by means of the cam C and the lever C, as in said prior application.

All parts of the machine not referred to by reference-letter or not shown in the accompanying drawings are constructed, arranged,

and operated as in said prior application.

E is the work-support, and E its pivoted carrier. E is the thread-controlling reciprocating bar connected to and movable endwise by the variable movements of the work-support when work of varying thickness is fed between the presser-foot d and the work-support.

F is the locking-lever, constructed, ar-

ranged, and operating precisely as in the before-cited prior patent except that the arrangement of the spring g 'for holding its rear arm or the truck 2' carried thereby, in contact with the cam i is located below the pin h, has its lower end connected directly to said lever F, and its upper end to the rod g which is threaded to receive the adjusting-nut g above the pin h, in which said rod 9 has its bearing.

J is a bracket bolted to the under side of the flange of the column B and projecting to the rear thereof to serve as a support for the Waxpot, which with the rear portion of said bracket is not shown. A smaller bracket J is bolted to the bracket J andhas mounted therein the spindle 0 upon which is mounted the tension-wheel J the pressure-disk 0 the spring 0 and spring compressing or adjusting nut 0 all of well-known construction.

K is a lever fulcrumed upon the same stud cam, (not shown, but precisely as in said prior 0 patent.) The rear end of said lever K has secured thereto the plate g which when dopressed serves as a brake-shoe to press upon the thread Q Within the groove of the tensionwheel to prevent the thread being drawn 5 therefrom when the shuttle is passing through the loop and when the stitch is being set. The lever D has a short rearwardly-proj ectin g arm, in the rear end of which is adjustably secured the pendent throad-ongaging arm r.

So far as now described the machine is constructed and operates as in said prior patent except as will be now described.

The pendent rod 1' is provided at its lower end with the enlarged forked portion 1- and has mounted between its two arms the antifriction-sheave r ,the groove in which engages the thread when the rear end of the lever D is depressed, the lower end of each arm of said fork 9'' being provided with an inwardly-projecting lug or shoulder r with its inner face inclined outward, as shown, which serves to guide the thread to the sheave and prevent all possibility of the thread getting between said sheave and its supporting-arms.

In the machine described in said prior patent the bar E was provided with a rearward extension form ed integral therewith or firmly secured thereto, upon'the rear end of which was mounted a thread-guiding sheave which was moved toward and from the tensionwheel according as the thickness of the sole fed between the presser-foot and the worksupport varied and caused a movement of the work-support and its carrier at the same time that the thread-measuring finger descended between said sheave and the tension-wheel to draw from said tension-wheel the requisite amount of thread for the next stitch, said thread-guiding sheave being prevented from being rotated backward, as will presently appear. While this device as constructed in said prior patent did vary the amount of thread drawn from the tension-wheel and source of supply as the position of the worksupport varied, it was found that it did not deliver quite the desired amount of thread, and to obviate this objection I mount upon the hub of the stand H, in which is set the stud j, the triangular arm L, having set in its rear end the stud 0*, upon which is mounted the sheave 4 having a V-shaped groove, the inner portion of which has parallel sides, the distance between which is not greater than the diameter of the thread to be used. The sheave T has formed upon its periphery, at one side of its groove, a series of ratchet-teeth with which the pawl r engages to prevent backward rotation of said sheave when the sheave r descends upon the thread and depresses it between said sheave r and the tension-wheel.

L is a link pivoted at one end to the lower corner of the triangular arm L and at its other end to the rear end of the bar E as shown in Fig. 2.

M is the shuttle; h the shuttle-race,which, with the devices for operating the shuttle, are constructed, arranged, and operated as shown and described in the before-cited application.

The thread Q after leaving the wax-pot (not shown) passes to and once around the tensionwheel J thence to and once around the sheave r thence over and under the sheaves on the ,arm R at the front of the machine, then through the eye of the looper, (not shown,) and thence to the work precisely as in said cited prior. patent.

The operation of my invention is as follows: If a piece of work of varying thickness is being sewed and the thin part is between the work-support and presserfoot and the thicker part is fed beneath the presserioot, the worksupport is depressed, the bar E is moved toward the rear, the locking-lever being raised from contact therewith by the action of the cam i upon the truck t and the arm L is moved about its axis of motion in the direction indicated by the arrow on Fig. 2, carrying the sheave r upward at the same time that the sheave r descends and carries downward a bight of the thread Q, thus increasing the length of thread drawn from the tensionwheel to correspond with the increased thickness of the work resting upon the work-support. If the work is fed from a thick to a thinner portion, the reverse action takes place and a less amount of thread is drawn from the tension-wheel, the sheave r being prevented from turning backward while the sheave r is drawing the thread from the tension-wheel by the stop-pawl r, as before described.

hat I claim as new, and desire to secure by Letters Patent of the United States, is-

1. In a lock-stitch waxed-thread sewingmachine,'the combination with a stitch-forming mechanism, of a yielding work-support; the bar E connected thereto and movable thereby; means for locking said bar and worksupport; a friction tension-wheel; the pivoted arm L located between said tension-wheel and work-support; the link L connecting the arm L and bar E the thread-guiding sheave 4' carried by the said arm L; the stop-pawl r"; the vertically-movable thread-depressing sheave r and means for imparting to said sheave r intermittent downward and upward movements.

2. In aloc-k-stitch sewing-machine, the combination with a stitch-forming mechanism, of a yielding work-support the bar E connected thereto and movable thereby; means for locking said bar and work-support; a frictional tension -wheel; a brake shoe for intermittently clamping the thread on said tensionwheel; means for intermittently depressing and raising said brake-shoe; the pivoted arm bar E, a thread-guiding sheave mounted on said arm L in near proximity to said tensionwheel but between it and the work-support, and freely revoluble in a forward direction; means for locking said sheave against backward revolution a vertically-movable threaddepressing antifriction-sheave; a forked hou sin g for said sheave the lower end of each fork of which is provided with inwardly-project ing guard-lug as set forth and means forintermittently actuating said thread-depressing sheave.

3. In a lock-stitch waxed-thread sewingmachinc, the combination of a pivoted yield- L'; the link L connecting said arm L and the.

ing sheave means for intermittently actuating said depressing-sheave; and means eonneeting said pivoted sheave-carrying arm and the work-support, whereby a downward movement of said Work-support will cause an upward movem ent of said th read-guidingsheave. In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, on this 26th day of May, A. D. 1899.

JOSEPH E. BERTRAND. Vitnesses N. O. LOMBARD, L. I. LA CHAPELLE. 

